There was no immediate reaction to the tanker's detention from Syria, which has suffered severe fuel shortages as a result of the civil war and Western sanctions that have crippled the country's oil industry, once the source of 20 per cent of government revenues. The target was somewhere else.
The government of Gibraltar said in a statement Monday that the tanker was "well inside" British Gibraltar Territorial Waters when it was boarded, having "previously exited the global waters of the Straits of Gibraltar".
He added that there was no law allowing authorities in Gibraltar to stop the tanker and called it "piracy".
Tehran has been in diplomatic contact with United Kingdom and the British ambassador has visited the Iranian foreign ministry twice since the arrest of the tanker Grace 1 at Gibraltar.
The incident occurred amid heightened tensions over Iran's unravelling 2015 nuclear deal with world powers, which the USA withdrew from past year. And EU as a principle doesn't impose its sanctions on others.
The threats, made by Tehran's nuclear agency spokesman, would go far beyond the small steps Iran has taken in the past week to nudge stocks of fissile material just beyond limits set out in the pact.